Most components used in finished goods undergo some sort of shape transformation prior to such use. As an extreme example, some components are injection molded of plastic and are ready (or virtually ready) to use at the completion of molding. Their shape is thus "transformed" from plastic granules to the finished part with very little or no final machining.
On the other hand, many other types of components require finish machining to place them in condition for use in finished goods. And that is true irrespective of whether the partially-completed component is brought to its "intermediate" form by casting, by fabrication or by some other means.
U.S. Pat. Nos. 144,214 (Mills) and 2,962,937 (Crise et al.) and German Patent 1 163 637 all relate to machining components from an intermediate to a finished (or more nearly finished) form. The Mills and German patents relate to gear machining and the arrangements described in those two patents involve using a "machine-based" device as a dimensional reference.
For example, the device shown in the German patent rotationally positions a gear by engaging it with a spring loaded feeler pin which is mounted on the machine used to cut the gear. In the attachment shown in the Mills patent, gear blanks are indexed for cutting gear teeth therein by engaging the point of a thumb screw with an index disk. The point engages a separate depression in the disk for each tooth to be cut. The index disk and the point are both mounted on the machine used for shaping the gear.
The method depicted in the Crise et al. patent is used to make cams and involves drawing a scribe line through the cam blank axis of rotation. Angles between each of several radials and the scribe line are used to calculate each of several tangents. A flat cut is then made at each tangent and, according to the patent, a curved cam surface results. Presumably, this requires a relatively large number of very closely spaced flat cuts to approximate a curved surface.
U.S. Pat. No. 4,512,694 (Foran et al.) involves a method and apparatus for aligning gears. After gear teeth are cut, a fixture with a radial arm and a head shaped like a truncated cone "picks up" a location from the teeth and uses such location to locate a keyway to be cut in the gear hub. While such fixture is gear, rather than machine, mounted, the accuracy with which the keyway is cut depends upon the accuracy of the fixture itself and upon its cone-shaped head part.
Similarly, the approach depicted in the Mills patent relies for its accuracy upon the accuracy with which the depressions are formed in an index disk and the accuracy with which the thumb-screw adjusted point is made. And it should be appreciated that all of the dimensional tolerances of the Foran et al. fixture, the Mills index disk and adjusted point are additive to the tolerances of the positioning accuracy of the cutting head (or other machining head) used by the machine tool to do the actual machining. The Crise et al. patent indicates the depicted method is for cutting radial type cams and gears that have irregular or non-circular profiles.
A new method for machining a component which addresses some of the problems and shortcomings of the prior art would be an important advance.